Low temperature capable lpg tank heater & pressure accumulator

Abstract

A system for providing LPG fuel to a fuel consuming unit, the system comprising: a storage tank configured to contain the LPG fuel; a heater configured to transfer heat to at least a portion of the LPG fuel; an accumulator configured to receive a portion of the LPG fuel; wherein the accumulator can apply pressure to the LPG fuel within the accumulator and the pressure being greater than the vapor pressure of the LPG fuel within the accumulator.

What is claimed is: 
     
         1 . A system for providing LPG fuel to a fuel consuming unit, the system comprising:
 a storage tank configured to contain the LPG fuel;   a heater configured to transfer heat to at least a portion of the LPG fuel;   an accumulator configured to receive a portion of the LPG fuel;   wherein the accumulator can apply pressure to the LPG fuel within the accumulator and the pressure being greater than the vapor pressure of the LPG fuel within the accumulator.   
     
     
         2 . The system of  claim 1 , further comprising:
 a first flowpath from the storage tank to a fuel delivery point;   a second flowpath from the accumulator to the fuel delivery point;   a third flowpath between the storage tank and the accumulator.   
     
     
         3 . The system of  claim 1 , wherein the system is capable of operating in a first mode and a second mode, in the first mode, the LPG fuel is delivered from the storage tank to a fuel delivery point, and in the second mode, the LPG fuel is delivered from the accumulator to the fuel delivery point and the pressure in the accumulator during operation in the second mode is greater than the vapor pressure of the LPG fuel in the accumulator during operation in the second mode. 
     
     
         4 . The system of  claim 3 , wherein the second mode allows operation of the fuel consuming unit when the temperature of the LPG fuel in the storage tank is too low to allow operation of the fuel consuming unit with the system operating in the first mode. 
     
     
         5 . The system of  claim 1 , wherein the accumulator is a bladder-type accumulator. 
     
     
         6 . The system of  claim 1 , further comprising an evaporator configured to convert liquid LPG fuel to gaseous LPG fuel. 
     
     
         7 . The system of  claim 1 , further comprising a controller for switching between utilizing a first energy source and a second energy source, wherein the first and second energy sources provide energy for the heater. 
     
     
         8 . The system of  claim 1 , wherein the heater is located partially inside and partially outside the storage tank. 
     
     
         9 . The system of  claim 8 , wherein the heater comprises:
 a first heat exchanger located at least partially inside the storage tank and in thermal communication with at least a portion of the LPG fuel within the storage tank;   a second heat exchanger located at least partially outside the storage tank, wherein the second heat exchanger is in thermal communication with the first heat exchanger; and   a heat source in thermal communication with the second heat exchanger.   
     
     
         10 . The system of  claim 8 , wherein the heat source is electrical. 
     
     
         11 . The system of  claim 7 , wherein the controller receives electrical input from the second energy source and switches between the first energy source and the second energy source based on the availability or unavailability of the second energy source. 
     
     
         12 . The system of  claim 11 , further comprising an electricity conditioner, wherein the electricity conditioner converts electricity between AC and DC electricity. 
     
     
         13 . A vehicle utilizing the system of  claim 1 . 
     
     
         14 . A system for providing an LPG fuel to a fuel consuming unit, comprising:
 A first LPG fuel delivery route, the first LPG fuel delivery route providing more than about 90% of the LPG fuel consumed by a fuel consuming unit when the LPG fuel exhibits a vapor pressure of less than a first pressure, the first LPG fuel delivery route including an accumulator capable of delivering the LPG fuel at a pressure greater than the vapor pressure of the LPG fuel within the accumulator; and   A second LPG fuel delivery route, the second LPG fuel delivery route providing more than about 90% of the LPG fuel consumed by the fuel consuming unit when the LPG fuel exhibits a vapor pressure of greater than a second pressure, wherein the first LPG fuel delivery route is not the same as the second LPG fuel delivery route,   wherein the first pressure is less than the second pressure.   
     
     
         15 . The system for providing LPG fuel of  claim 14 , wherein the first LPG fuel delivery route and the second LPG fuel delivery route share at least one component. 
     
     
         16 . A vehicle utilizing the system of  claim 14 . 
     
     
         17 . A control system for an LPG fuel delivery system, the control system comprising:
 a circuit, wherein the circuit switches power delivered to a tank heater from a first electrical source to a second electrical source in an LPG fuel delivery system, and wherein the LPG fuel delivery system comprises a storage tank capable of containing an LPG fuel, a first flow path from the storage tank to a fuel delivery point, a second flow path from the storage tank to the fuel delivery point, An accumulator located along the second flow path, and a heater configured to transfer heat to at least a portion of the LPG fuel.   
     
     
         18 . The control system of  claim 17 , wherein the LPG fuel in the storage tank exhibits a vapor pressure, and more than 90% of the LPG fuel delivered to the delivery point is delivered from the accumulator when the vapor pressure is less than a first pressure, and more than 90% of the LPG fuel delivered to the delivery point is delivered from the storage tank when the vapor pressure is more than a second pressure, the first pressure being less than the second pressure. 
     
     
         19 . A system for providing LPG fuel to a fuel consuming unit, the system comprising:
 a storage tank capable of containing an LPG fuel;   a first flow path from the storage tank to a fuel delivery point;   a second flow path from the storage tank to the fuel delivery point, wherein the first flowpath and the second flowpath partially coincide;   an accumulator located along the second flow path, the accumulator configured to deliver LPG fuel at a pressure above the vapor pressure of LPG fuel within the accumulator;   a heater comprising a resistive electrical heating element, and configured to transfer heat to at least a portion of the LPG fuel, wherein the heater is located partially inside and partially outside the storage tank, and comprises a first heat exchanger located at least partially inside the storage tank and is in thermal communication with at least a portion of the LPG fuel within the storage tank, and a second heat exchanger located at least partially outside of the storage tank and is in thermal communication with the first heat exchanger, and an electrical heat source in thermal communication with the second heat exchanger;   a controller for switching between utilizing a first energy source and a second energy force, wherein the first and second energy sources provide energy for the heat source, wherein the controller receives electrical input from the second energy source and switches between the first energy source and the second energy source based on the availability or unavailability of the second energy source; and   an electricity conditioner, wherein the electricity conditioner converts electricity between AC and DC electricity.   
     
     
         20 . A vehicle utilizing the system of  claim 19 .